Toxocariasis – Are your Pets a Threat?

24 June 2023
Posted by: Chelsea

Human infection by parasites of the above general type is considered by the United Nations to be one of the top underestimated diseases globally.

Given the link between pet faeces and this illness, how safe is your child with your household pets?

What is Toxocariasis?

Toxocariasis, a condition which refers to infection by a parasitic worm.

Typically, the worm inhabits the intestines of certain animals, notably domestic cats and dogs. That’s important because although it may also be found in some other animals (e.g., foxes), the majority of close human contact with animals associated with infection in the western world is through household pets.

Although humans are not the preferred Toxocariasis carrier and host for the worm, they can compromise and adapt to human beings.

The infection cycle

The mature worm typically lives in the stomach and intestines of its host.

At a certain point, it will produce microscopic eggs which are passed out through faeces. Initially, these eggs pose little danger but after maturing for around 2 weeks in the sand or soil where they were deposited, they can become active and will in turn infect another host if they’re eaten.

The disease typically cannot be directly passed on human-to-human by close contact.


Most humans with a normal robust immune system should be able to quickly deal with ingested eggs and therefore notice no Toxocariasis symptoms.

Some groups though may be far more vulnerable to an infection with subsequent health symptoms involving the growth of the worm or worms in the body. They include:

  • babies and younger children, who may not yet have fully developed immune systems;
  • pregnant women;
  • people suffering from other serious illnesses or those on immune-suppressant drugs;
  • older and frailer people.


Even where a worm has developed and grown inside the body, the host may still be asymptomatic and not even know they’re infected. It may though be possible to sometimes see active worms in the faeces.

In other fairly rare cases, the worm’s development may take place in various parts of the body other than the intestine, notably the lungs, liver and eyes.

As such, symptoms may vary considerably. They may include:

  • fever;
  • rashes
  • stomach pain/cramps;
  • coughing or difficulty in breathing
  • blindness in one eye, spots before the eye, blurred vision or light flashes.

The risks;

As the UN believes that infections are hugely under-estimated around the world, it is very difficult to realistically assess the risk for children in Australia.

However, as far as is known, in Australia as a whole, there have only ever been 5-10 Toxocariasis cases confirmed. This suggests that Toxocariasis is a rare condition – at least insofar as infections manifesting symptoms.


This is usually effective and involves taking drugs designed to kill and clear the worms. Sometimes surgery may also be required.


Children though are at particular risk because of their love of pets plus their tendency to like to play on soil or in sand. A small messy finger covered in soil and then put into the mouth could be carrying worm eggs.

There are some good sensible practices that should help make this even less likely to arise:

  • wash your child’s hands thoroughly if they’ve been playing outside and are coming in to eat;
  • do likewise with your own hands before preparing food;
  • where possible, do not permit your domestic animals to defecate in your garden;
  • if your children have a sand-pit, cover it securely overnight to stop other pets or wild animals from using it as a toilet;
  • don’t let your pets lick your children’s mouths or faces;
  • avoid sharing plates or utensils with animals;
  • ensure your pets are regularly wormed.

Make sure your children understand the importance of hygiene and avoiding animal faeces. However, don’t make them inhibited about playing outside and getting dirty. The risks of infection are small and your children need the exposure to nature!

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